Polarization independent optoelectronic device and method

ABSTRACT

A device includes a scattering structure and a collection structure. The scattering structure is arranged to concurrently scatter incident electromagnetic radiation along a first scattering axis and along a second scattering axis. The first scattering axis and the second scattering axis are non-orthogonal. The collection structure includes a first input port aligned with the first scattering axis and a second input port aligned with the second scattering axis. A method includes scattering electromagnetic radiation along a first scattering axis to create first scattered electromagnetic radiation and along a second scattering axis to create second scattered electromagnetic radiation. The first scattering axis and the second scattering axis are non-orthogonal. The first scattered electromagnetic radiation is detected to yield first detected radiation and the second scattered electromagnetic radiation is detected to yield second detected radiation. The first detected radiation is phase aligned with the second detected radiation.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application62/753,142, titled, “POLARIZATION INDEPENDENT OPTOELECTRONIC DEVICE ANDMETHOD” and filed Oct. 31, 2018, which is incorporated herein byreference.

BACKGROUND

The rapid expansion in the use of the Internet has resulted in a demandfor high speed communications links and devices, including optical linksand devices. Optical links using fiber optics have many advantagescompared to electrical links: large bandwidth, high noise immunity,reduced power dissipation, and minimal crosstalk. Optoelectronicintegrated circuits made of silicon are useful since they can befabricated in the same foundries used to make very-large scaleintegrated (VLSI) circuits. Optical communications technology istypically operating in the 1.3 μm and 1.55 μm infrared wavelength bands.The optical properties of silicon are well suited for the transmissionof optical signals, due to the transparency of silicon in the infraredwavelength bands of 1.3 μm and 1.55 μm and the high refractive index ofsilicon.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 illustrates a top view of an optoelectronic device in accordancewith some embodiments.

FIG. 2 illustrates a top view of an optoelectronic device comprising anoptical combiner associated with the collection structure in accordancewith some embodiments.

FIG. 3 illustrates a top view of an optoelectronic device comprising anelectrical combining circuit associated with the collection structure inaccordance with some embodiments.

FIG. 4 illustrates a circuit diagram of an electrical combining circuitcomprising phase tuning elements in accordance with some embodiments.

FIG. 5A illustrates a circuit diagram of a phase tuning element inaccordance with some embodiments.

FIG. 5B illustrates a circuit diagram of a phase tuning element inaccordance with some embodiments.

FIG. 6 illustrates a top view of an optoelectronic device comprisingmultiple input ports and associated photodetectors in accordance withsome embodiments.

FIGS. 7-15 illustrate views of scattering structures in accordance withsome embodiments.

FIG. 16 illustrates a flow diagram of a method for phase aligningscattered electromagnetic radiation in accordance with some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Optoelectronic devices are employed to communicate optical signals,through a medium, such as a fiber optic cable, for example. On areceiving end of the medium, an optoelectronic receiver collectsincident electromagnetic radiation and performs an optical-to-electricalconversion to allow processing of the information carried on theincident electromagnetic radiation. In some embodiments, anoptoelectronic device comprises a scattering structure to scatter theincident electromagnetic radiation and a collection structure comprisinginput ports positioned proximate the scattering structure to collect thescattered electromagnetic radiation. The collected scatteredelectromagnetic radiation is provided to one or more photodetectors toperform an optical-to-electrical conversion. In some embodiments, theinput ports are positioned at different radial positions around aperiphery of the scattering structure, where the radial positions defineoblique angles with respect to a center point of the scatteringstructure. In some embodiments, the scattering structure concurrentlyscatters incident electromagnetic radiation along non-orthogonalscattering axes, and the input ports are aligned in the collectionstructure with the non-orthogonal scattering axes. In some embodiments,the incident electromagnetic radiation exiting the medium is verticallypolarized. However, the particular orientation of the orthogonalcomponents of the vertically polarized electromagnetic radiationimpinging on the collection structure is indeterminate. As will bedescribed in detail below, the relative positioning of the input portsin the collection structure enhances polarization independence of theoptoelectronic device.

Referring now to FIG. 1, a top view of a portion of an optoelectronicdevice 100 in accordance with some embodiments is illustrated. Theoptoelectronic device 100 comprises a scattering structure 105 and acollection structure 110. In some embodiments, a medium 115, such as afiber optic cable, etc. terminates proximate the optoelectronic device100. Electromagnetic radiation 120 exits the medium 115 and impinges onthe scattering structure 105. Electromagnetic radiation reflected fromthe scattering structure 105 is received into the collection structure110. In some embodiments, the medium 115 is positioned at an obliqueangle with respect to a horizontal plane comprising the scatteringstructure 105. According to some embodiments, width and lengthdimensions of the scattering structure 105 are about twice thecorresponding width and length dimensions of the medium 115. In someembodiments, the electromagnetic radiation 120 is vertically polarized.A “vertically polarized” electromagnetic wave comprises an electricfield vector and a magnetic field vector at a right angle with respectto the electric field vector. Both the electric field vector andmagnetic field vector are perpendicular to the direction of propagation.According to some embodiments, the scattering structure 105 scatters theelectromagnetic radiation 120 along scattering axes 125A, 125B, 125Cthat are non-orthogonal with respect to one another. In someembodiments, the number and orientation of the scattering axes 125A,125B, 125C varies. In accordance with some embodiments, certainscattering axes are orthogonal to one another, but non-orthogonal toother scattering axes, such that at least a first scattering axis 125Ais non-orthogonal with respect to at least a second scattering axis125B.

In some embodiments, the collection structure 110 comprises input ports130, which are referred to individually as input ports 130(1) . . .130(n). In some embodiments, the input ports 130 are positioned around aperiphery of the scattering structure 105. In some embodiments, theinput ports 130 collectively continuously cover an entire periphery ofthe scattering structure 105. In some embodiments, particular adjacentinput ports 130 collectively cover continuous portions of a periphery ofthe scattering structure 105. In some embodiments, the input ports 130cover portions of the periphery of the scattering structure 105 in anon-continuous manner. In some embodiments, the collection structure 110comprises at least three input ports 130. In some embodiments, thecollection structure 110 is divided into at least three sectors, eachsector having at least one input port 130. According to someembodiments, the input ports 130 are silicon structures or wave guidesthat direct the incident electromagnetic radiation.

According to some embodiments, the input ports 130 are positioned atdifferent radial positions around the scattering structure 105 withrespect to a center point 135 of the scattering structure 105. Forexample, the input port 130(1) is at a first radial position 140(1), andthe input port 130(2) is at a second radial position 140(2). The radialpositions 140(1), 140(2) define an oblique angle 145 with respect to thecenter point 135 of the scattering structure 105.

According to some embodiments, certain input ports 130 are aligned withthe scattering axes. For example, the input port 130(3) is aligned withone end of the scattering axis 125A, and the input port 130(4) isaligned with an opposite end of the scattering axis 125A.

Referring to FIG. 2, a top view of the optoelectronic device 100comprising an optical combiner 200 associated with the collectionstructure 110 in accordance with some embodiments is illustrated. Insome embodiments, the collection structure 110 comprises input ports 130(which are referred to individually as 130(1) . . . 130(n)) positionedaround a periphery of the scattering structure 105. The input ports 130comprise wave guides that extend to the optical combiner 200. Accordingto some embodiments, the optical path lengths of the wave guides to theoptical combiner 200 are substantially equal such that the signalspropagated therein are phase aligned. In some embodiments, the inputports 130 and associated wave guides comprise silicon structuresembedded in a dielectric material. In some embodiments, the opticalcombiner 200 is a multi-mode interferometer, such as a 6:1 multi-modeinterferometer. An optical output of the optical combiner 200 is coupledto a photodetector 205. The photodetector 205 outputs a signal having aproperty that is indicative of the intensity of the electromagneticradiation output by the optical combiner 200. For example, in someembodiments, the photodetector 205 outputs a current that isproportional to or otherwise indicative of the intensity of theelectromagnetic radiation output by the optical combiner 200. As anotherexample, in some embodiments, a voltage generated at an output of thephotodetector 205 is proportional to or otherwise indicative of theintensity of the electromagnetic radiation output by the opticalcombiner 200. Thus, the output of the photodetector 205 is an electricalmeasure of the signal provided by the medium 115. Transitions in theoutput of the photodetector 205 correspond to edges in theelectromagnetic signal.

In some embodiments, the input ports 130(1), 130(4) are aligned withopposite ends of the scattering axis 125A, the input ports 130(2),130(5) are aligned with opposite ends of the scattering axis 125B, andinput ports 130(3), 130(6) are aligned with opposite ends of thescattering axis 125C. According to some embodiments, the number andorientation of the scattering axes 125A-125C generated by the scatteringstructure 105 corresponds to the number and position of the input ports130. In some embodiments, the layout of the input ports 130 defines aperiphery of the scattering structure 105. For example, the scatteringstructure 105 in FIG. 2 has a hexagonal periphery corresponding to thelayout of the input ports 130. In some embodiments, the scatteringstructure 105 defines an N-sided polygon, where N equals the number ofinput ports 130 in the collection structure. In some embodiments,although the polygons have linear edges, the overall shape approximatesa circle with respect to a center point of the scattering structure 105.

Referring to FIG. 3 a top view of the optoelectronic device 100comprising an electrical combining circuit 300 associated with thecollection structure 110 is illustrated in accordance with someembodiments. In some embodiments, the periphery of the scatteringstructure 105 and the layout of the input ports 130(1)-130(6)corresponds to that described above in reference to FIG. 2. In someembodiments, each input port 130(1)-130(6) is coupled to a respectivephotodetector 305(1)-305(6). In some embodiments, the photodetectors305(1)-305(6) are germanium based PiN diodes and the dimensions of eachphotodetectors are about 20 um in length and about 0.5 um in width.

In some embodiments, the photodetectors 305(1)-305(6) are coupled to anamplifier 310 in the electrical combining circuit 300 that generates avoltage proportional to a magnitude of a current received at an input ofthe electrical combining circuit 300. Each of the photodetectors305(1)-305(6) generates an output signal indicative of or proportionalto the electromagnetic radiation passing through the associated inputport 130(1)-130(6). The electrical combining circuit 300 combines theindividual signals from the photodetectors 305(1)-305(6) to generate anoutput signal providing an electrical measure of the signal provided bythe medium 115. Transitions in the output of the electrical combiningcircuit 300 correspond to edges in the electromagnetic signal.

Referring to FIG. 4, a circuit diagram of an electrical combiningcircuit 400 comprising phase tuning elements 405 is illustrated inaccordance with some embodiments. In some embodiments, the phase tuningelements 405 are coupled between the photodetectors 305 (e.g., thephotodetectors 305(1)-306(6) in FIG. 3) and an amplifier 410. The phasetuning elements 405 allow phase alignment of the individual signals fromthe photodetectors 305. According to some embodiments, the phase tuningelements 405 are configured by measuring phase differences between theindividual photodetectors 305 and adjusting a variable delay generatedby the phase tuning elements 405. In some embodiments, a rising orfalling edge in the output signal of each photodetector 305 is detected.The delay generated by each phase tuning element 405 is adjusted untilthe falling or rising edges are phase aligned across the photodetectors305. In some embodiments, a controller 415 dynamically tunes the phasetuning elements 405 during operation of the optoelectronic device 100.In some embodiments, the phase tuning elements 405 are staticallyconfigured based on characterization tests performed on theoptoelectronic device 100 during a design phase.

Referring to FIG. 5A, a circuit diagram of a phase tuning element 405 isillustrated in accordance with some embodiments. In some embodiments,the phase tuning element 405 comprises delay stages 505 that introduce adelay in the signal propagating through the phase tuning element 405. Insome embodiments, each delay stage 505 comprises a resistor 510 and acapacitor 515. In some embodiments, the total delay of the phase tuningelement 405 is configured by varying the number of delay stages 500. Insome embodiments, one or more of the resistors 510 are variableresistors, where the resistance is varied based on a bias voltageapplied to the resistor 510, such as applied by the controller 415. Insome embodiments, one or more of the capacitors 515 are variablecapacitors, where the capacitance is varied based on a bias voltageapplied to the capacitor 515, such as applied by the controller 415.

Referring to FIG. 5B, a circuit diagram of a phase tuning element 405 isillustrated in accordance with some embodiments. In some embodiments,the phase tuning element 405 comprises delay stages 520 that introduce adelay in the signal propagating through the phase tuning element 405. Insome embodiments, each delay stage 520 comprises an inductor 525 and acapacitor 530. In some embodiments, the total delay of the phase tuningelement 405 is configured by varying the number of delay stages 520. Insome embodiments, one or more of the inductors 525 are variableinductors, where the inductance is varied based on a bias voltageapplied to the inductor 525, such as applied by the controller 415. Insome embodiments, one or more of the capacitors 530 are variablecapacitors, where the capacitance is varied based on a bias voltageapplied to the capacitor 530, such as applied by the controller 415.

Referring to FIG. 6, a top view of the optoelectronic device 100comprising a large number of input ports 130, each having an associatedphotodetector 305, according to some embodiments is illustrated. In someembodiments, the electrical combining circuit 300 illustrated in FIG. 3is coupled to the photodetectors 305 illustrated in FIG. 6. In someembodiments, the electrical combining circuit 400 illustrated in FIG. 4is coupled to the photodetectors 305 illustrated in FIG. 6. As seen inFIG. 6, as the number of photodetectors 305 increases, the periphery ofthe scattering structure 105 approaches a circular shape. According tosome embodiments, the number of input ports 130 and associatedphotodetectors 305 vary depending on the available circuit area aroundthe scattering structure 105. In some embodiments, with the scatteringstructure 105 having a perimeter of about 62 um and the photodetectors305 having a width of about 0.5 um and a pitch of about 2 um, the numberof photodetectors 305 is 31.

Referring to FIGS. 7-15 various views of scattering structures areillustrated in accordance with some embodiments. According to someembodiments, the scattering structure may be employed in theoptoelectronic devices 100 described above.

Referring to FIG. 7, a top view of a scattering structure 105A isillustrated in accordance with some embodiments. In some embodiments,the scattering structure 105A comprises pillars 700 arranged in a grid705. In some embodiments, the spacing of the pillars 700 in the grid 705is periodic. In some embodiments, the spacing of the pillars 700 in thegrid 705 is irregular. According to some embodiments, the pillars 700have a circular horizontal cross-sectional shape. The circularhorizontal cross-sectional shape of the pillars 700 results in a largenumber of non-orthogonal scattering axes (not illustrated). In someembodiments, the scattering structure 105A is employed with theoptoelectronic device 100 of FIG. 6 to facilitate the large number ofradially positioned input ports 130.

Referring to FIG. 8, a top view of a scattering structure 105B isillustrated in accordance with some embodiments. In some embodiments,the scattering structure 105B comprises pillars 800 arranged in a grid805. In some embodiments, the spacing of the pillars 800 in the grid 805is periodic. In some embodiments, the spacing of the pillars 800 in thegrid 805 is irregular. According to some embodiments, the pillars 800have a triangular horizontal cross-sectional shape. The triangularhorizontal cross-sectional shape of the pillars 800 results in theelectromagnetic radiation being scattered along the scattering axes125A, 25B, 125C. In some embodiments, each edge of a pillar 800 isreferred to as a facet, where each pillar has at least one facetoriented perpendicular to one of the scattering axes 125A, 125B, 125C.In some embodiments, each facet of a pillar 800 is orientedperpendicular to a different one of the scattering axes 125A, 125B,125C. In some embodiments, the scattering structure 105B is employedwith the optoelectronic device 100 of FIGS. 3 and 4.

Referring to FIGS. 9-11, a top view, an isometric view, and across-section view of a scattering structure 105C, respectively, areillustrated in accordance with some embodiments. In some embodiments,the scattering structure 105C comprises pillars 900 arranged in a grid905. In some embodiments, the spacing of the pillars 900 in the grid 905is periodic. In some embodiments, the spacing of the pillars 900 in thegrid 905 is irregular. According to some embodiments, the pillars 900each have a lower member 900A and an upper member 900B positioned on thelower member 900A. According to some embodiments, the lower member 900Aand the upper member 900B have different horizontal cross-sectionalshapes. In some embodiments, the lower member 900A has a trapezoidalhorizontal cross-sectional shape. In some embodiments, the upper member900B has a circular horizontal cross-sectional shape. Varying thehorizontal cross-sectional shapes of the lower member 900A and the uppermember 900B allows the creation of various arrangements ofnon-orthogonal scattering axes for the scattering structure 105C, forexample. In some embodiments, the circular horizontal cross-sectionalshape results in substantially even scattering of the incidentelectromagnetic radiation toward the collection structure 110. In someembodiments, polygon shapes are employed to provide multiple scatteringaxes, and as the number of faces in the polygon increases, thescattering characteristics approach that of a circle.

Referring to FIG. 11, a cross-section view of the grid 905 along line11-11 shown in FIG. 9 according to some embodiments is illustrated. Insome embodiments, the scattering structure 105C is formed on a substratehaving a semiconductor-on-insulator (SOI) configuration that comprises abulk semiconductor layer 1100, a buried insulation layer 1105, a firstsemiconductor layer 1110 in which the lower members 900A are formed, anda second semiconductor layer 1115 in which the upper members 905B areformed. In some embodiments, the first semiconductor layer 1110 and thesecond semiconductor layer 1115 may comprise the same or differentcompositions of materials. In some embodiments, the first semiconductorlayer 1110 and the second semiconductor layer 1115 are portions of thesame semiconductor layer that are differentiated by an etching process.In some embodiments, the buried insulation layer 1105 is exposed betweenthe pillars 900. According to some embodiments, patterned etchingprocesses are performed to define the lower member 900A and the uppermember 900B. In some embodiments, the bulk semiconductor layer 1100 issilicon. In some embodiments, the bulk semiconductor layer 1100 is amaterial other than silicon, such as silicon-germanium, a III-V compoundsemiconductor material, etc. In some embodiments, the buried insulationlayer 1105 is silicon dioxide or other suitable dielectric. In someembodiments, the first semiconductor layer 1110 and the secondsemiconductor layer 1115 are silicon.

Referring to FIGS. 12-13, a top view and an isometric view of ascattering structure 105D, respectively, in accordance with someembodiments are illustrated. In some embodiments, the scatteringstructure 105D comprises pillars 1200 arranged in a grid 1205. In someembodiments, the spacing of the pillars 1200 in the grid 1205 isperiodic. In some embodiments, the spacing of the pillars 1200 in thegrid 1205 is irregular. According to some embodiments, the pillars 1200each have a lower member 1200A and upper member 1200B positioned on thelower member 1200A. According to some embodiments, pillars 1200 aresimilar to the pillars 900 described in FIGS. 9-11, with the exceptionthat an opening 1210 is defined through the upper member 1200B and thelower member 1200A to expose the underlying buried insulation layer 1105(shown in FIG. 11).

Referring to FIGS. 14-15, a top view and an isometric view of ascattering structure 105E, respectively, in accordance with someembodiments are illustrated. In some embodiments, the scatteringstructure 105E comprises pillars 1400 arranged in a grid 1405. In someembodiments, the spacing of the pillars 1400 in the grid 1405 isperiodic. In some embodiments, the spacing of the pillars 1400 in thegrid 1405 is irregular. According to some embodiments, the pillars 1400each have a lower member 1400A and upper members 1400B(1)-1400B(3)positioned on the lower member 1400A. According to some embodiments, thelower member 1400A has a trapezoidal horizontal cross-sectional shape.In some embodiments, the upper members 1400B(1)-1400B(3) have triangularhorizontal cross-sectional shapes. Varying the horizontalcross-sectional shapes of the lower members 1400A and upper members1400B(1)-1400B(3) allows the creation of various arrangements ofnon-orthogonal scattering axes for the scattering structure 105E, forexample.

In some embodiments, the scattering structures illustrated in FIGS. 7-15are implemented on a semiconductor wafer. In some embodiments, thesemiconductor wafer has a semiconductor-on-insulator (SOI) configurationthat comprises a bulk semiconductor layer, a buried insulation layer,and at least one semiconductor layer in which the elements of thescattering structures are formed. FIG. 11 illustrates such an SOIsubstrate in reference to one embodiment of a scattering structure 105C.The same substrate configuration may be employed for the otherscattering structures 105A, 105B 105D, 105E illustrated in FIGS. 7, 8,and 12-15, for example.

Referring to FIG. 16 a flow diagram of a method 1600 for phase aligningscattered electromagnetic radiation is illustrated in accordance withsome embodiments. At 1605, electromagnetic radiation is scattered alonga first scattering axis to create first scattered electromagneticradiation and along a second scattering axis to create second scatteredelectromagnetic radiation. In some embodiments, the first scatteringaxis and the second scattering axis are non-orthogonal. At 1610, thefirst scattered electromagnetic radiation is detected to yield firstdetected radiation, and the second scattered electromagnetic radiationis detected to yield second detected radiation. At 1615, the firstdetected radiation is phase aligned with the second detected radiation.

In some embodiments, an optoelectronic device comprises a scatteringstructure to scatter the incident electromagnetic radiation and acollection structure comprising input ports positioned proximate thescattering structure to collect the scattered electromagnetic radiation.The collected scattered electromagnetic radiation is provided to one ormore photodetectors to perform an optical-to-electrical conversion. Insome embodiments, the incident electromagnetic radiation exiting themedium is vertically polarized. However, the particular orientation ofthe orthogonal components of the vertically polarized electromagneticradiation impinging on the collection structure is indeterminate. Therelative positioning of the input ports in the collection structureenhances polarization independence of the optoelectronic device.

In some embodiments, a device includes a scattering structure and acollection structure. The scattering structure is arranged toconcurrently scatter incident electromagnetic radiation along a firstscattering axis and along a second scattering axis. The first scatteringaxis and the second scattering axis are non-orthogonal. The collectionstructure is arranged to collect the scattered electromagnetic radiationand includes a first input port aligned with the first scattering axisand a second input port aligned with the second scattering axis.

In some embodiments, a device includes a scattering structure and acollection structure. The scattering structure is arranged to scatterincident electromagnetic radiation. The collection structure is arrangedaround a periphery of the scattering structure to collect the scatteredelectromagnetic radiation. The collection structure includes a firstinput port positioned at a first radial position around the periphery ofthe scattering structure and a second input port positioned at a secondradial position around the periphery of the scattering structure. Thefirst radial position and the second radial position define an obliqueangle with respect to a center point of the scattering structure.

In some embodiments, a method includes scattering electromagneticradiation along a first scattering axis to create first scatteredelectromagnetic radiation and along a second scattering axis to createsecond scattered electromagnetic radiation. The first scattering axisand the second scattering axis are non-orthogonal. The first scatteredelectromagnetic radiation is detected to yield first detected radiationand the second scattered electromagnetic radiation is detected to yieldsecond detected radiation. The first detected radiation is phase alignedwith the second detected radiation.

The foregoing outlines features of several embodiments so that those ofordinary skill in the art may better understand various aspects of thepresent disclosure. Those of ordinary skill in the art should appreciatethat they may readily use the present disclosure as a basis fordesigning or modifying other processes and structures for carrying outthe same purposes and/or achieving the same advantages of variousembodiments introduced herein. Those of ordinary skill in the art shouldalso realize that such equivalent constructions do not depart from thespirit and scope of the present disclosure, and that they may makevarious changes, substitutions, and alterations herein without departingfrom the spirit and scope of the present disclosure.

Although the subject matter has been described in language specific tostructural features or methodological acts, it is to be understood thatthe subject matter of the appended claims is not necessarily limited tothe specific features or acts described above. Rather, the specificfeatures and acts described above are disclosed as example forms ofimplementing at least some of the claims.

Various operations of embodiments are provided herein. The order inwhich some or all of the operations are described should not beconstrued to imply that these operations are necessarily orderdependent. Alternative ordering will be appreciated having the benefitof this description. Further, it will be understood that not alloperations are necessarily present in each embodiment provided herein.Also, it will be understood that not all operations are necessary insome embodiments.

It will be appreciated that layers, features, elements, etc. depictedherein are illustrated with particular dimensions relative to oneanother, such as structural dimensions or orientations, for example, forpurposes of simplicity and ease of understanding and that actualdimensions of the same differ substantially from that illustratedherein, in some embodiments. Additionally, a variety of techniques existfor forming the layers, regions, features, elements, etc. mentionedherein, such as at least one of etching techniques, planarizationtechniques, implanting techniques, doping techniques, spin-ontechniques, sputtering techniques, growth techniques, or depositiontechniques such as chemical vapor deposition (CVD), for example.

Moreover, “exemplary” is used herein to mean serving as an example,instance, illustration, etc., and not necessarily as advantageous. Asused in this application, “or” is intended to mean an inclusive “or”rather than an exclusive “or”. In addition, “a” and “an” as used in thisapplication and the appended claims are generally be construed to mean“one or more” unless specified otherwise or clear from context to bedirected to a singular form. Also, at least one of A and B and/or thelike generally means A or B or both A and B. Furthermore, to the extentthat “includes”, “having”, “has”, “with”, or variants thereof are used,such terms are intended to be inclusive in a manner similar to the term“comprising”. Also, unless specified otherwise, “first,” “second,” orthe like are not intended to imply a temporal aspect, a spatial aspect,an ordering, etc. Rather, such terms are merely used as identifiers,names, etc. for features, elements, items, etc. For example, a firstelement and a second element generally correspond to element A andelement B or two different or two identical elements or the sameelement.

Also, although the disclosure has been shown and described with respectto one or more implementations, equivalent alterations and modificationswill occur to others of ordinary skill in the art based upon a readingand understanding of this specification and the annexed drawings. Thedisclosure comprises all such modifications and alterations and islimited only by the scope of the following claims. In particular regardto the various functions performed by the above described components(e.g., elements, resources, etc.), the terms used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (e.g., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure. In addition, while aparticular feature of the disclosure may have been disclosed withrespect to only one of several implementations, such feature may becombined with one or more other features of the other implementations asmay be desired and advantageous for any given or particular application.

What is claimed is:
 1. A device, comprising: a scattering structurecomprising a plurality of pillars positioned over a top surface of asubstrate, wherein: the plurality of pillars are arranged toconcurrently scatter incident electromagnetic radiation along a firstscattering axis and along a second scattering axis, the first scatteringaxis and the second scattering axis are non-orthogonal, and theplurality of pillars comprises silicon; and a collection structure tocollect the scattered electromagnetic radiation, wherein the collectionstructure comprises: a first input port aligned with the firstscattering axis; a second input port aligned with the second scatteringaxis; a first waveguide to guide the scattered electromagnetic radiationreceived at the first input port; and a second waveguide to guide thescattered electromagnetic radiation received at the second input port.2. The device of claim 1, wherein the first input port and the secondinput port collectively collect the scattered electromagnetic radiationalong a continuous region of a periphery of the scattering structure. 3.The device of claim 1, comprising: a first photodetector coupled to thefirst input port through the first waveguide; a second photodetectorcoupled to the second input port through the second waveguide; and anamplifier coupled to the first photodetector and the secondphotodetector to generate an output signal.
 4. The device of claim 3,comprising: a first phase tuning circuit coupled between the firstphotodetector and the amplifier; and a second phase tuning circuitcoupled between the second photodetector and the amplifier.
 5. Thedevice of claim 4, comprising: a controller to configure the first phasetuning circuit and the second phase tuning circuit to phase align thefirst photodetector and the second photodetector.
 6. The device of claim1, wherein the device comprises: an optical combiner coupled to thefirst waveguide and the second waveguide, wherein the first waveguidehas a first path length and the second waveguide has a second pathlength substantially equal to the first path length; and a photodetectorcoupled to the optical combiner.
 7. The device of claim 1, wherein eachpillar of the plurality of pillars has a triangular horizontal crosssectional shape.
 8. The device of claim 1, wherein each pillar of theplurality of pillars comprises: a first member having a first horizontalcross-sectional shape; and a second member having a second horizontalcross-sectional shape different than the first horizontalcross-sectional shape and positioned on the first member.
 9. The deviceof claim 1, wherein: a first pillar of the plurality of pillars has afirst facet positioned perpendicular to the first scattering axis; and asecond pillar of the plurality of pillars has a first facet positionedperpendicular to the second scattering axis.
 10. The device of claim 1,wherein the collection structure comprises: a third input port alignedwith the first scattering axis and positioned at an opposite end of thefirst scattering axis relative to the first input port; and a fourthinput port aligned with the second scattering axis and positioned at anopposite end of the second scattering axis relative to the second inputport.
 11. A device, comprising: a scattering structure comprising aplurality of pillars positioned over a top surface of a substrate,wherein the plurality of pillars is arranged to scatter incidentelectromagnetic radiation; and a collection structure arranged around aperiphery of the scattering structure to collect the scatteredelectromagnetic radiation, wherein the collection structure comprises: afirst input port positioned at a first radial position around aperiphery of the scattering structure; and a second input portpositioned at a second radial position around the periphery of thescattering structure, wherein: each of the first input port and thesecond input port comprises silicon embedded in a dielectric material,and the first radial position and the second radial position define anoblique angle with respect to a center point of the scatteringstructure.
 12. The device of claim 11, wherein the first input port andthe second input port collectively collect the scattered electromagneticradiation along a continuous region of the periphery of the scatteringstructure.
 13. The device of claim 11, comprising: a first photodetectorcoupled to the first input port; a second photodetector coupled to thesecond input port; and an amplifier coupled to the first photodetectorand the second photodetector to generate an output signal.
 14. Thedevice of claim 13, comprising: a first phase tuning circuit coupledbetween the first photodetector and the amplifier; and a second phasetuning circuit coupled between the second photodetector and theamplifier.
 15. The device of claim 14, comprising: a controller toconfigure the first phase tuning circuit and the second phase tuningcircuit to phase align the first photodetector and the secondphotodetector.
 16. The device of claim 11, comprising: a first waveguidecoupled to the first input port; a second waveguide coupled to thesecond input port; an optical combiner coupled to the first waveguideand the second waveguide, wherein the first waveguide has a first pathlength and the second waveguide has a second path length substantiallyequal to the first path length; and a photodetector coupled to theoptical combiner.
 17. The device of claim 11, wherein each pillar of theplurality of pillars comprises: a first member having a first horizontalcross-sectional shape; and a second member having a second horizontalcross-sectional shape different than the first horizontalcross-sectional shape and positioned on the first member.
 18. The deviceof claim 11, wherein the plurality of pillars comprises silicon.
 19. Amethod, comprising: receiving electromagnetic radiation at a scatteringstructure comprising a plurality of pillars to scatter electromagneticradiation along a first scattering axis to create first scatteredelectromagnetic radiation and along a second scattering axis to createsecond scattered electromagnetic radiation, wherein the first scatteringaxis and the second scattering axis are non-orthogonal; detecting thefirst scattered electromagnetic radiation at a first input port to yieldfirst detected radiation and detecting the second scatteredelectromagnetic radiation at a second input port to yield seconddetected radiation; and phase aligning the first detected radiation withthe second detected radiation.
 20. The method of claim 19, wherein thephase aligning comprises: configuring a variable delay of a phase tuningcircuit to phase align the first detected radiation with the seconddetected radiation.